Now very early stage of development.
I will upload source soon later at:
http://code.google.com/p/wikipediaconv/
Only test enwiki-20110901-pages-articles1.xml.bz2 now.
My hard disk is too small to convert all dump data (does anyone want to try?)
Main target is EZ-Reader, and my goal is support Japanese version (but only enwiki until now).
If your e-book device support folder and epub, you can also use it.
Any feedback is welcome though I might not have enough time to modify this code other than Japanese support.